1. Field of the Invention
The present invention concerns the prevention of disease transmission occurring from accidental sharp, or needle sticks with spent or contaminated medical needles.
2. Description of Relevant Art
Accidental needle stick injuries are common amongst health care workers such as doctors, nurses, laboratory personnel, and housekeeping personnel. Accidental needle sticks with contaminated needles can result in the transmission of diseases including Acquired Immune Deficiency Syndrome (AIDS), Hepatitis B, Non-A-Non-B Hepatitis, and other diseases transmissable through the blood. The severe health hazards and consequences associated with these diseases have resulted in well-thought-out protocols for handling medical needles and a near universal use of needle and syringe disposal containers.
Notwithstanding the care taken with contaminated medical needles, it is estimated in the publication Bio-Medical International, Vol. IX. 23-24 for December, 1986 that "an estimated 800,000 sharp or needle sticks occur each year in the U.S.". It is further estimated that "primary treatment (glamma globulin, hepatitis B immune globulin, tetanus) and subsequent blood analysis and care costs . . . $600-$1,000 per incident". This figure may be compared with a similar report that "each needle stick injury costs a hospital more than $200.00" in U.S. Pat. No. 4,592,744 filed Aug. 14, 1985. Whatsoever the actual prevalence and actual cost of an accidental needle stick injury, it is indisputable that each such injury is psychologically disconcerting to the health care worker receiving the injury.
Accidental needle sticks may often occur when a drawer of blood, or any administrator injecting a patient, attempts to recap or dispose of a needle, syringe, or vacuum tube phlebotomy system after use. Although modern health care protocols seldon allow for any prolonged exposure of a contaminated needle upon a work surface, in some instances a contaminated needle is set upon a work surface by one person, normally the administrator, and subsequently removed for disposal by another person, normally an assistant or nurse. During the course of this handling and interchange accidental self-sticks and sticks of other persons occasionally occur.
In order to reduce the numbers of accidental needle sticks during necessary handling, a number of needle sheathing systems have been developed within the prior art. These systems generally show a sheathing or a resheathing of a needle by dealing with the entire injection apparatus, or syringe, to which the needle is connected. In many instances the needle will be withdrawn within a syringe, or the entire syringe will be covered by sliding covers.
The present invention will be seen to be distinguished from such prior art in one aspect by dealing with the sheathing of a needle directly at and along the length of the needle itself, as opposed to sheathing any syringe or ampoule to which the needle is connected. Particularly, the needle sheating scheme in accordance with the present invention exhibits in a first general embodiment a localized locking member, i.e. a bead or protuberance, rigidly positioned along the length of the needle. The locking member is cooperatively interactive with a sliding tubular sleeve coaxially positioned along the length of the needle in order to selectively retain this sleeve in a position sheathing the end of the needle. Although such a sheathing scheme needs to be given a broad interpretation, and although the means of engaging and retaining a sliding tubular sleeve need not appear exactly as a locking bead or protuberance which is positioned directly upon the needle, the present invention does involve a sleeve which slides along the needle in order to sheath the needle, and a retaining or locking mechanism for such slidable sleeve which retaining mechanism is in a fixed relationship to the needle. This should be contrasted to a prior art sheathing devices which either (i) slide along a syringe, or are (ii) replaceably removable from the needle. By such differences and other differences, the present invention may be observed to comprise a significant unobvious departure from the prior art.
In particular, the following is a list of U.S. Patents which exemplify the current state of art: U.S. Pat. Nos. 4,592,744; 4,507,117; 4,392,859; 4,373,526; 4,273,123; 4,266,544; 4,139,009; 3,890,971; 3,485,239; 3,356,089; 3,306,291; 3,306,290; 2,925,083; 2,888,923; 2,847,966; 2,847,995.
U.S. Pat. No. 4,592,744 shows a syringe which is self-resheathing within a case when the needle is withdrawn.
U.S. Pat. No. 4,507,117 shows a syringe with a needle retractable into the barrel of the syringe.
U.S. Pat. No. 4,392,859 shows an automatic injecting device having a spring-biased retracting needle.
U.S. Pat. No. 4,373,526 shows a protective closure for a hypodermic needle which may receive and retain the needle after it is removed from, or broken off, the end of the syringe.
U.S. Pat. No. 4,266,544 shows a device on the end of a syringe apparatus which renders a needle inoperable subsequent to being used.
U.S. Pat. No. 4,139,009 shows a retractable cover means for a hypodermic.
U.S. Pat. No. 3,890,971 shows a safety feature for syringes which, subsequent to being used, locks the plunger and needle such that it is incapable of being reused.
U.S. Pat. No. 3,485,239 shows a self-contained syringe wherein the hypodermic needle is initially situated within a barrel.
U.S. Pat. No. 3,356,089 shows a needle sheath and guide, particularly for selectable penetration control.
U.S. Pat. No. 3,306,291 shows the use of frangible connections in combination with syringes and the like.
U.S. Pat. No. 3,306,290 shows the use of a spring-biased retractable syringe.
U.S. Pat. No. 2,925,083 shows a hypodermic syringe with a hood for guarding the needle.
U.S. Pat. No. 2,888,293 shows a syringe within a coaxial protective tube.
U.S. Pat. No. 2,847,996 shows the use of a hypodermic having two barrel-like compartments.
U.S. Pat. No. 2,847,995 shows the use of retractable needle within a rubber sheath.
As a further point of comparison of the prior art to the present invention, it should be additionally observed that the referenced patents show unique apparatus constructions which are generally incompatible to be assimilated with or retrofitted upon any pre-existing standard disposable syringe or needle (such as those commonly manufactured by market leaders Becton Dickinson or Sherwood). The present invention is, to the contrary, readily adaptable to pre-existing disposable needles and syringes that are made by major manufacturers. The apparatus of the present invention, in certain variants, is adaptable to such pre-existing needles and syringes by retrofit. Alternatively, the apparatus of the present invention may, in other variants, be directly incorporated in medical needles and syringes upon initial manufacture.